So this started a while back on my 855i it started surging around the 3 to 4k RPM range. It was due a service so I did.
- New Battery, Oil and filters, Spark plugs
- Replaced all the worn gaskets in the airbox and around the IACV
- Cleaned Throttle bodies, IACV, Throttle springs etc.
- Balanced throttle bodies
- Replaced fuel filter
- Replaced ruptured oil drain tube in airbox
- Replaced fuel hoses
- Reconnected the airbox to fuel tank hose (which for some reason was unattached)
Was absolutely grand for about 500 miles then the surging returned.
- Balanced the throttle bodies again (balance was lost), added some loctite because screws felt loose.
After about 50 miles the surging returned.
- Was not far out of balance.
-Stripped down screws, cleaned springs, reassembled, balanced the throttle bodies, added more loctite and some silicone gasket to the screws for good measure.
- Replaced vacuum hoses.
Riding was absolutely fantastic for 80 miles, then surging worse than ever, almost bloody dropped it on a tight manoeuvre. If I hold the throttle at about 3k it's surging by 500 RPM either side, which means it's practically unrideable, and deteriorating.
Surging seems to stop at around 6k RPM.
Any ideas?
Don't know if the fuel map on the ECU could be the issue. It seem sodd that the surgeing keeps returning, almost as if the ECU is resetting itself, especialy given the distance it appears to take to upset the balance.
Sadly, I'm no ECU guru so am clutching at straws here.
Also forgot to add why I replaced the vacuum hoses, the bike was cutting out when the clutch was pulled once warm. This isn't happening now, even though the surging is occuring.
I have plugged in TuneECU. It tells me that I have an un-registered bike and to contact them...
I have thought about the 12 minute tune but probably best not when it's 5C outside as it recommends a much higher air temp.
Now you mention fuel map. When I got the bike the fuel pressure regulator to airbox hose was not fitted. I thought that might be the mechanic, because they did a few other weird things too.
If the fuel map is off, that might explain it, but then the 50-80 mile rides feel very random.
Have you tested for air leaks around the connection between carbs and engine?
I sprayed a bit of wd40 around the IACV to see if there was a leak there because the housing at the screw is cracked. Seems OK though. I also sprayed around the throttle body, where I could reach and the hoses once I fitted the new ones to see if they had leaks.
I'd be surprised if it's a mapping issue because the map has not been deliberately changed since it was bought, and I trust the previous owner on that one.
Possibly also worth saying no engine warning lights are on.
Some standard things that I'm sure you've checked...make sure vacuum hoses are on the correct IACV nipple. One of those nipples is intentionally blocked. Also, the hose that goes from the air box back to the computer should be installed. Lastly, does your bike have an O2 sensor delete plug installed?
Fuel pump or fuel pressure?. can you check the actual pressure?, I noted you mentioned fuel pressure pipe was disconnected. maybe it was disconnected for a reason?
Quote from: London_Phil on March 14, 2024, 09:53:01 AMFuel pump or fuel pressure?. can you check the actual pressure?, I noted you mentioned fuel pressure pipe was disconnected. maybe it was disconnected for a reason?
Yup I thought it might be, but according to other forums it does nothing because the pressure differential is basically zero. So I think it less likely. The surging seems odd if it's a pressure problem, would indicate pump ramping up and down...
It is always hard to diagnose issue when lots of components are disturbed. Did you clean the eventual tank slime sediments and clean pump strain mesh?
"- Reconnected the airbox to fuel tank hose (which for some reason was unattached)"
I have the same bike, but can't figure the hose you mentioned. May you explain more, please.
That must be the vacuum hose to the regulator?
Quote from: the slow heart on March 16, 2024, 10:34:37 AMIt is always hard to diagnose issue when lots of components are disturbed. Did you clean the eventual tank slime sediments and clean pump strain mesh?
"- Reconnected the airbox to fuel tank hose (which for some reason was unattached)"
I have the same bike, but can't figure the hose you mentioned. May you explain more, please.
That must be the vacuum hose to the regulator?
Yes, vacuum hose to fuel pressure regulator. I have read it does very little, so doubt that's the cause.
Cleaned sediments and mesh.
To answer above from another poster, all vacuum hoses on the IACV are attached to correct nipples.
I would try to isolate the problem by checking/replacing just one item at a time and then the next etc.
New battery? Would attach volt meter and observe what happens round 3k rpm, to verify alternator is ok.
New fuel filter? Would test with bypassed pressure guage to confirm 3+/-0.25 bars, to verify also pump is ok.
Vacuum regulator? Would deattach the hose and test.
iacv lines, are they soft silicone that might shrink on suction increase or be pinched by oher items?
ecu mapping, why would not reinstall the standard map for the model and be able to see all the tests and diagnostic data? Prev setup does not matter since all is disturbed in fuel system. I had similar issue with outdated map.
Note carefully the throttle grip position for this 3k rpm in neutral. Then remove the tank and airbox, and observe in detail the throttle items movement when you adjust throttle arround this position. Any slack anywhere? Stripped threads are no good.
All sensors have their nominal testing parameters in the manual. You could check them also. I would start with the tps.
Quote from: the slow heart on March 17, 2024, 08:55:51 AMI would try to isolate the problem by checking/replacing just one item at a time and then the next etc.
New battery? Would attach volt meter and observe what happens round 3k rpm, to verify alternator is ok.
New fuel filter? Would test with bypassed pressure guage to confirm 3+/-0.25 bars, to verify also pump is ok.
Vacuum regulator? Would deattach the hose and test.
iacv lines, are they soft silicone that might shrink on suction increase or be pinched by oher items?
ecu mapping, why would not reinstall the standard map for the model and be able to see all the tests and diagnostic data? Prev setup does not matter since all is disturbed in fuel system. I had similar issue with outdated map.
Note carefully the throttle grip position for this 3k rpm in neutral. Then remove the tank and airbox, and observe in detail the throttle items movement when you adjust throttle arround this position. Any slack anywhere? Stripped threads are no good.
All sensors have their nominal testing parameters in the manual. You could check them also. I would start with the tps.
General update - tested while stationary
- TPS appears to be at 0.6% when closed, so need to adjust this.
- When at 3500 rpm TPS is constant but RPM is fluctuating by +/-200, IGN values also constant.
- When I turned the ignition key for the first time since my original post it made an odd noise, either the IACV or the fuel pump? Started fine though.
- Map is 9880 but I have not read it to break it down.
- Detached vacuum regulator hose, no appreciable difference.
Will take tank off later today to inspect vacuum lines and re-check balancing.
Tough fight you have :icon_scratch:
Is there any chance for debris in fuel system?
I have not cleaned injectors for instance, but two years ago sipped a bottle of Bardhal injector cleaner in the tank, just for the peace of mind.
For more info, I noted the throttle bodies were very slightly unbalanced, I have balanced them to dead on and used instant gasket and threadlocker to try to prevent them slipping, maybe this time it will work! I have re-tubed one of the vacuum hoses that was slightly kinked, but wasn't pinched shut. Airbox went back on then I reset the TPS.
Idle is now at 1200 RPM and fluctuating by +/- 80 RMP rather than +/- 50 RPM.
Sounds quite rough idling even though the engine is warm.
Revving to 3000 RPM, there's about a +/-100 RPM fluctuation, better than +/-500 RPM...
Adjustments : IACV set to 120, Idle fuel trim @ 16.4, Long term fuel trim @ 0
Still with 1601 Indicator Lamp error code.
Debris in the fuel system... Possible but I worked clean when I changed the filter. Will try running some injector cleaner through it.
Fixed 1601, the engine light lamp had come out of it's connection, easy fix.
If after each dismantling you find throttles bit off balance, you might be right to prime suspect worn screws.
When you blow with mouth at iacv, are all three lines equally releasing air? When you continue blowing and finger block orifices at manifold, do you feel pressure block and silence? O ring under the valve should be good.
What about the spark plugs?
When you cleaned the carbs, did you really push something through all of the needles and thoroughly did the same with all of the other little passageways within the carbs?
I did an ultrasonic cleaning session on the carbs of my Ducati and then I needed to do it again. ;)
Uploaded the latest map, no difference.
"If after each dismantling you find throttles bit off balance, you might be right to prime suspect worn screws."
Possible but threads look in good condition
"When you blow with mouth at iacv, are all three lines equally releasing air? When you continue blowing and finger block orifices at manifold, do you feel pressure block and silence? O ring under the valve should be good."
Oring appears fine, will blow into IACV to check...
"What about the spark plugs?"
All new and gapped correctly.
"When you cleaned the carbs, did you really push something through all of the needles and thoroughly did the same with all of the other little passageways within the carbs?"
Used carb cleaner spray from liquimoly to clean throttle body inlets, will be ordering new seals for injectors, will clean the injectors and replace the seals when I do. Also trying to get an EFI relay, and a throttle body housing.
If the fuel map is updated and no test/sensor misbehave, the possibility of electrical issue gets less. Is there easy way to check that all three spark plugs fire at required frequency?
And since problem is in lower rpm some air leak still might cause the erratic situation. Injector seals renewal is a good move in that sense. You could think further which seals are exactly broken during your work, and how to check all of them for sure after the problem shows again ( since threads/screws seals are intact ). If you try to reproduce the problem with iacv socked unplugged from the el.looming, what happens?
Good luck!
So today I addressed a sticky throttle cable, not a cause. Then installed a new IACV housing and more rigid hoses, just in case.
I checked the balancing screws, they were annoyingly loose, I could turn them with my fingers on the heads... So will get some new loctite.
Got some throttle bodies from a broker, the screws were so much stiffer, so will re-balance with the new ones, came with injectors so will be cleaning them and selecting the best. Hopefully this will sort it. Otherwise fuel pump will be coming out, which is a bit of a pain I'd rather not have to work on.
Big respect for sticking with this, many would have got shot of the bike by now.
Looking forward to seeing you resolve the issues & having a fully functioning bike.
Thanks, was my dad's bike so it's not just a bike. Also I'm an engineer, so I spend my whole life trying to work out why things are broken.
Today I cleaned the injectors and fuel rail.
Battery needs a charge before it'll start again, so fingers crossed tomorrow.
At this rate it'll be running next January...
Cleaning injectors did not help...
My long term fuel trim seems to have set itself really weird too, was down at -60, I have tried to reset this, but unfortunately the slider on the TuneECU app is playing up (only for the trim) and if I select any number highlighted it jumps to another random number, ie. -10 jumps to +80 and then 0 to -80 and +10 to +60. Doesn't make sense so have a TuneECU query on this as it seems to be a UI issue on the app.
The engine is quite sporadic now, it's fluctuations have worsened, at idle it will stall or bring itself up to around 3000rpm.
On the plus side I think I'm getting there. The fuel pump is noise when priming is getting worse, a very noticeable squeal now. Considering replacing that, the fuel pressure regulator and the filter. Could do with measuring the fuel pressure really but the Triumph part is extortionate. Does anyone know how to read the pump voltage?
Why exactly OEM gauge, you could easily improvise with another pressure gauge reading max at least 5 Bar.
Pump voltage also, the el.socket is not super tight, so two thin wires could be put in the female orifices before plugging the socket, then use these two for your volt meter.
Have to check was there an easy way to clear long term trims.
Quote from: the slow heart on April 16, 2024, 11:34:15 AMWhy exactly OEM gauge, you could easily improvise with another pressure gauge reading max at least 5 Bar.
Exactly what I did in the end.
Pump voltage also, the el.socket is not super tight, so two thin wires could be put in the female orifices before plugging the socket, then use these two for your volt meter.
Have to check was there an easy way to clear long term trims.
So the pressure seems good, basically at 3 bar(g) consistently, even when it runs up the revs or stalls.
I have managed to find the number which changes LTFT to 3.0 (slider error still unresolved), much closer to 0 than -60.
So what I am seeing now.
At LTFT around 0 it fails turns over but doesn't rev to idle.
At LTFT around -10 it will remain stable but burning rich and smelly throttle response is slow to opening or closing.
At LTFT around -30 the application of the throttle will cause it to run up through the revs, even when throttle released.
So either burning rich or not at all. The opposite problem of previous lean burning.
I'm starting to think major vacuum leak from somewhere. Partly because if I manually cover the IACV to restrict air flow at idle it's still pulling air in from somewhere... Also looking at the throttle body vacuum it's far lower than it was when I last tried balancing it.
Potentially it's a throttle body gasket? Or maybe something else...
Still to replace injector seals, they arrived today.
Waiting injector seals replacement to rule them out.
Do you have lambda on the exhaust? Which map is on board now?
So when I took apart the injectors this time I noticed damage to a seal. Replaced all seals, they slid in much easier this time during assembly.
Assessed current situation.
Adjustments : IACV set to 120, Idle fuel trim @ 16.4, Long term fuel trim @ +3
Engine starting is difficult with failing to rev, when it does start it revs to approximately 1200 RPM before cutting out.
Map is 9892, Yes Lambda sensor is there.
For good measure, and because it is easy I am going to re-check my spark plugs to see if they've fouled since put in.
Also worth noting that the fuel rail pressure on priming is 2.8 bar (g) and this drops to 2.6 bar (g) over 5 mins when engine is off. Fuel pump is squealing slightly during priming, however when I start the engine it keeps pressure.
Also noted in the manual that the cutting out could be a stuck IACV, which it is not, or a blocked throttle body 1 way valve... so I will look into that too.
Replaced fuel pump and hoses for good measure. Squealing has stopped, and the fuel pump reaches pressure faster. It started making a gushing sound when ignition is turned, I sent an inspection camera into the tank and it appears to be coming from the fuel pressure regulator, which I guess is how it works.
I also cannot find any 1 way valve between the throttle bodies and the IACV... I have blown down the IACV pipes, through the IACV housing too in order to check for blockages, all seems OK.
Keep it up man, the bike just gets better :eusa_clap
Hope spark plugs inspection won't raise more issues like piston ring or valve guide leaks, beware how much you torque them in thereafter. Are the plugs Denso, or NGK equivalent? In my location NGK cheap replicas are more common.
If the lambda is not working properly, it may override proper iacv co setting. On the safe side you better test it with a meter, wash it after gasoline soaking. You could also test unplug it from the loom to simulate open loop system and load the 9891 map. After the test load back 9892 and plug the sensor.
Pump priming may be less pressure due to less voltage. More important is when bike is running, voltage high ( how much is it at idle actually ? ). Anyway you are within 10% of the 3 bar requirement.
Might be the questioned one way valve is within the iacv itself, get it off and mouth blow it both sides to check whether it is one or two way open?
Any chance crank shaft position sensor to be disturbed? It is well exposed during clutch/ valve train works.
Cheers man,
Plugs are NGK probably about 300 miles through them, although I will need to double check as apparently fakes do exist and they were mail order...
I haven't done the valves or clutch, so the only way that the Crankshaft Position Sensor could be off would be some slippage.
The valve clearances are due a service, but I want to get it going again first. Will try some of these lambda sensor fixes and blow the otherway into the IACV.
Spark plugs were black with carbon! Will be cleaning or renewing before carrying on. Although I am not sure that this is the main issue because it was still running with -ve adjustment on the LTFT.
So this is a little funny, and slightly embarrassing.
It turns out that the lambda sensor on my exhaust is not plugged in, and never has been. The cat on the exhaust must have got replaced after an accident I'm guessing from a scrapped bike. So this would explain a lot.
I have loaded the 9891 map and it's working again. I have also replaced the spark plugs due to the fouling, and set all the trims back to 0.
I am back to square 1. The bike is working, throttle bodies are balanced but it's still surging.
Looking at the pump pressure this seems fine.
What I have noticed is that there appears to be some backfiring, into cylinder 2 which is not noticeable when throttle is open, but when it is closed you can hear a hiss and see a small flash in throttle body 2, there is no popping in throttle body 2 when the throttle valves are open. I am slightly concerned that I can see a flash in body 2, as this means it's not fully air tight when closed, although it appears balanced with the throttle touching the motion limiting screw.
So here's some numbers at idle @1180 RPM
Ignition Timing is at 4.5deg target dwell times of 1.8, 1.8, 1.9ms and Ignition Pulse times of 1.801, 1.696 and 1.740ms(in 1,2,3 order)
@1260 RPM
Ignition Timing is at 5.5deg target dwell times of 1.9, 1.8, 1.8ms and Ignition Pulse times of 1.798, 1.737 and 1.904ms(in 1,2,3 order)
The valve shims do need to be done too at some point, but I am wondering if my injector in cylinder 2 is leaking slightly.
We all have our funny and unforgettable memories from the garage :icon_salut:
This manifold backfire suggests inlet valve on no.2 is not completely closing and compression phase pumps back air/fuel mixture in the manifold, exploding with some correlation to no.2 firing time. It is serious suspicion that could lead to valve/piston further complications. I would do valve clearances first and check compression after. Then if no.2 shows lower pressure, head has to go off and valve seat potential damage cleared out until it is withing recoverable limits. Fiddling with fuel mapping should be no priority in such situation :m
Oh good. I'll get on with it then.
Hopefully no lasting damage.